How do I get details of downstream builds triggered asynchronously?

I have a Jenkins pipeline that triggers a downstream job using the build step.

I'd like to know the URL of the downstream job as soon as it starts, however, if I specify wait: false, then (as per the documentation) there is no return value from the build step (it's a NullObject).

Is the a way to access information on the triggered downstream build (specifically its URL) after it is triggered but before it completes?